Method of making non-woven fibrous web



June 24, 1969 J. J. KLEIN 3,451,109

METHOD OF MAKING NON-WOVEN FIBROUS WEB Filed Nov. 18, 1968 United StatesPatent 3,451,109 METHOD OF MAKING NON-WOVEN FIBROUS WEB Joseph J. Klein,Beverly Hills, Califi, assignor to Union Carbide Corporation, acorporation of New York Continuation-impart of application Ser. No.712,312,

Dec. 27, 1967. This application Nov. 18, 1968, Ser.

Int. Cl. D04h 18/00 US. Cl. 2872.2 Claims ABSTRACT OF THE DISCLOSURE Anon-Woven material having a divided pile-like surface is achieved byneedling a portion of the fibers of the non-woven material into a sheetof flexible foam and then peeling the foam away to leave the pile-likesurface.

RELATED APPLICATIONS This application is a continuation-in-part of mycopending US. application Ser. No. 712,312, filed Dec. 27, 1967, nowabandoned which is in turn a division of my U.S. application Ser. No.208,345 filed July 9, 1962, now abandoned.

This invention relates to a method of making nonwoven fibrous web havinga pile on at least one surface. In accordance with the method of thisinvention there is produced a non-woven fibrous web having a pile on atleast one free surface, said pile comprising staple fibers lying normalto said surface and projecting therefrom.

In carrying out the method of this invention a nonwoven fibrous webcomprising fibers of staple length, preferably a low density fibrousweb, is needled to an elastomeric sheet to cause a portion of the staplefibers of said web to lie in a direction substantially normal to asurface of said web and to project from said surface into saidelastomeric sheet. The elastomeric sheet is thereafter stripped fromsaid fibrous web leaving said projecting staple fibers lying in adirection substantially normal to said surface.

The low density non-woven fibrous web is made up of staple fibers whichmay lie randomly or may be substantially parallel, as in a card, airlaid, or water laid web. Preferably the non-woven web is a low densityweb of high 10ft wherein the fibers are in a helter-skelter arrangementand in a three-dimensional lie. These webs are known materials. Theelastomeric layer is generally a flexible foam, although other porouselastomeric materials such as sponge elastomer, or even non-porouselastomers such as crepe rubber may also be used.

The non-woven fibrous web and the flexible foam are temporarily bondedto each other by the needling. The passage of closely spaced barbedneedles through the fibrous web and into the flexible foam partiallycompresses the web to a higher density and causes the staple fiberswhich are engaged by the barbs on the needles to lie in a directionsubstantially normal to the surface of the non-woven fibrous web and toproject therefrom into the flexible foam. The fibers may projectentirely through the flexible foam or they may penetrate only part ofthe way through. For ease of stripping in some applications it ispreferred that the penetration of staple fibers into the flexible foamshall not be through the entire thickness of said foam, but only througha portion thereof. For such partial penetration of the fibers, theneedle penetration should be such that the forwardmost barb of theneedle does not pass through the entire thickness of the flexible foam.For other applications, such as those where a stronger bond is desiredprior to stripping, total penetra- 3,451,109 Patented June 24, 1969 tionof the fibers, even to the extent of some fibers projecting through onthe other side of the foam, is preferred.

Friction between the flexible foam and the staple fibers projectingtherein holds the fibers relatively tightly and causes them to maintaintheir projecting direction after the foam is stripped away. Thus thereis obtained a nonwoven fibrous web having a pile surface.

The non-woven fibrous web having a pile surface may be used withoutfurther processing for uses such as insulating interliners in clothing.Ordinarily, however, further processing and particularly the spraying ofthe pile surface with a resinous material and the bonding of the fiberswith adhesive which may be the same resinous material used in the pilesurface spray, is desirable. The amount and nature of the resinousmaterial sprayed is related to the use to which the web is to be put.Both thermosetting and thermoplastic resinous materials arecontemplated.

One of the most important applications of the web of this inventioninvolves its use as automotive carpeting. For such use, a relativelyheavy resinous spray, or a spray of rubber or other rubbery material, ofthe order of about 3 to 5 ounces per square yard is used to impart thedesired strength and wear resistance to the web. More or less resin orrubber material is used to meet the requirements of other applications.Other applications include use as household carpeting, filtering mediaand furlike materials.

The invention may be more readily understood by reference to thedrawings in which FIGURE 1 is a partial perspective view of the webmaterial of this invention; FIGURE 2 is an enlarged sectional view ofthe web material; FIGURE 3 is a side elevation with portions of theapparatus shown in section, illustrating the process for making the webmaterial; and FIGURE 4 is an enlargement of a zone of FIGURE 3 wherepeeling takes place.

In a specific embodiment described with reference to the drawings, abatt 11 of staple fibers which crisscross each other in a random,helter-skelter, three-dimensional relationship, is passed at a rate of10 feet per minute onto a flexible moving belt 12. The belt has apermanent woven inner layer 13 and a removable polyurethane foam outerlayer 14. The polyurethane foam is /2" thick and has a density of 1 /2lbs. per cubic foot.

Batt 11 is composed of wt. percent of 16 denier cellulose acetate 2"staple and 20 wt. percent of 15 denier 2" nylon staple. The staplefibers are crimped with about 8 crimps per inch. The batt is 54 wide.

The batt and belt pass to a conventional needling machine 16 wherebarbed needles 17 are passed through the batt and into the foam layer ina rapid reciprocating action. The spacing of the needles and the numberof strokes per minute are adjusted to provide 300 punches per squareinch in the batt. The length of stroke is adjusted either for completeor partial penetration of the foam layers. For the latter the adjustmentcan be such that the forwardmost barbs of the needles pass about intothe foam layer and do not reach its inner surface. The belt is supportedunder the needling area by a perforated plate, not shown.

After passing through the needling machine the batt is reduced to about4" thickness and is needled to foam layer 14. Each penetration of abarbed needle produces a fiber punch 18 in the batt where the staplefibers which make up the batt are aligned in a direction perpendicularto the batt and project into the foam layer. The needling fixes thestaple fibers in the fibrous web relative to each other at spaced pointsand fixes the batt to the flexible foam layer at spaced points.

Although the batt is securely affixed to the foam layer by the frictionof the foam against the perpendicular fibers 3 in the many fiber punches18, the two may be readily separated by a peeling action which applies aseparating force to only a few fiber punches at a time. Such a peelingaction is provided by the change of direction of the belt as it passesover its terminal roller 19.

The perpendicular staple fibers which extend into the flexible foamlayer retain their perpendicular direction after the stripping actionand now extend as projections or pile 21 beyond the free surface 22 ofthe fibrous web.

If further processing is desired, the pile web now passes over rollers23 and 24 to change the direction of the projections or pile fromdownward to upward and to facilitate the application of the resinousand/or rubber coating through spray nozzle 26. Resinous material orrubber material or a mixture of such materials, is applied through thenozzle in the amount of about 3 ounces per square yard. The resinousmaterial is a liquid epoxy resin (Shell Epon 828) which is a reactionproduct of bisphenol A and epichlorohydrin having an epoxy number ofabout 190 grams per epoxide equivalent and a hydroxy number of about 80grams per hydroxy equivalent. The rubber material may be natural rubberor similar synthetic rubbery material in the form of a latex.

The sprayed web material is then passed through a dryer 27 maintained atabout 325350 F. The adhesive coating is dried and cured in the dryer. Inthe case of the liquid epoxy resin the drying is effected during aresidence period of about four minutes. The finished web material,suitable for automotive floor covering, is taken up on roll 28.

The resin or rubber material, or a mixture of the same, serves to impartstrength and wear resistance to the pile. It also serves to impartstrength and wear resistance to the web itself since the resin and/orrubber material enters the body of the web and binds the fibers at theintersections. If greater strength is desired in the web the side of thesame opposite the pile is sprayed with adhesive material to further bindthe fibers at the intersections and the sprayed web is then again curedas described. The spray coating of the web and the curing thereof asdescribed is conventional.

Although the invention has been described in detail with respect to aparticular embodiment thereof, it is to be understood that numerousdepartures and modifications are possible within the scope thereof andaccording to the specific requirements of the intended use.

For example, the original non-woven fibrous batt may be made of anystaple fiber which lends itself to the formation of a non-woven needledfibrous batt for a particular purpose. The staple fiber may be a naturalstaple such as cotton or wool, or a man-made staple such as viscose orcuproammonium rayon fibers, nylon fibers, acrylic or modacrylic fibers,polyester fibers, polyolefin fibers or polyacetal fibers. The denier ofthe fibers may vary considerably, a suitable range being from about 3 toabout 22 denier. The staple fiber is preferably crimped, usually havingbetween about 3 and about 15 crimps to the inch. The staple length mayvary considerably from about A to about 4". Mixtures of fibers may beused in the batt and a small proportion, say up to about 15% by weight,may be shorter fibers down to and including fibers of papermakinglength.

The weight of the batt may also vary depending on the intended use. Asuitable range is from about 2 to about 20 ounces per square yard. Thethickness of the batt after needling (excluding the pile) may vary asdesired, suitably from about Vs" to about /2".

The needling rate and the spacing of the needles may be varied toproduce more closely spaced fiber punches, a suitable range being fromabout 150 to about 350 fiber punches per square inch. The depth of theneedle punch (the penetration of the forwardmost barbs) can be selectedto be greater than, equal to or less than the thickness of the foam beltand is suitably between about Ms" and about /2 or more, depending on theuse to which the web is to be put.

The process may also be modified in details without departing from thescope of this invention. If desired, for example, the needling may beupward with the needles penetrating the batt from below and passing intothe foam layer of a belt above the batt. In such a case the pileprojections from the web are upward projections and the web is sprayedconveniently without reversing its direction.

The foam layer of the belt may vary in composition, density orthickness, as required. The foam layer is removable since it loses itsstrength after several hours or days of needling and must be replaced.

In place of the epoxy resin disclosed above, other resinous materials,natural rubber and synthetic rubbers may be used in the spray. Theresinous material may be elastomeric or non-elastomeric, thermoplasticor thermosetting, depending on the use to which the final product is tobe put. The resinous material may be in the form of a solution or in theform of a latex. Both homopolymers and copolymers may be used.

Suitable resins include thermosetting materials such as epoxy resins andmelamine resins; vinyl and vinylidene resins, such as polyvinylchloride, polyvinyl acetate and polymethyl methacrylate; and syntheticelastomeric materials such as the rubbery copolymer of butadiene andacrylonitrile sold under the trademark Hycar.

For automotive carpeting, as stated above, a relatively heavy spraycoating of an epoxy resin is preferred although elastomeric resins maybe used if desired.

For other purposes, relatively light sprays of the order of one ounceper square yard may be preferred so that the individual fibers of thepile do not become bonded to each other. For a synthetic fur-like web, alight spray is used, followed by electrification and shearing of thepile fibers to uniform length.

When the pile fibers are not sheared, it will be found on closeexamination that some are looped and some are not. The unlooped fibersare believed to be formed when the needle barbs engage staple fibersnear their ends or when the staple fibers are torn during needling.

The dryer temperatures and residence times are adjusted to meet therequirements of the particular resins, rubbers and concentrationsthereof used.

What is claimed is:

1. A method of preparing a non-woven fibrous web having a pile whichcomprises driving a plurality of closely spaced needles through an openlow density web made of a plurality of staple fibers and into anadjacent layer of elastomeric material and thereafter peeling saidfibrous web away from said elastomeric layer.

2. A method according to claim 1 wherein the penetration of said needlesis limited to avoid passing fibers through the entire thickness of saidelastomeric material.

3. A method of preparing a non-woven fibrous web having a pile whichcomprises driving a plurality of closely spaced needles through an openlow density web made of a plurality of staple fibers and into anadjacent layer of flexible foam material and thereafter peeling saidfibrous web away from said elastomeric layer.

4. A method according to claim 3 wherein the penetration of said needlesis limited to avoid passing fibers thrlough the entire thickness of saidflexible foam mater1a 5. A method according to claim 3 wherein saidflexible foam material is a foam layer on an endless belt.

6. A method according to claim 4 wherein said flexible foam material isa foam layer on an endless belt.

7. A method of preparing a non-woven fibrous web having a pile whichcomprises driving a plurality of closely spaced needles through an openlow density web made of a plurality of staple fibers and into anadjacent layer of flexible foam material and thereafter peeling saidfibrous web away from said elastomeric layer.

through the entire thickness of said flexible foam ma terial.

9. A method of preparing a non-woven web having a pile which comprisesdriving a plurality of closely spaced needles through a non-wovenfibrous web comprising fibers of staple length and into an adjacentlayer of elastomeric material and thereafter peeling said fibrous webaway from said elastomeric layer.

10. A method according to claim 9 wherein the penetration of saidneedles is limited to avoid passing fibers through the entire thicknessof said elastomeric material.

6 References Cited UNITED STATES PATENTS 2,429,486 10/ 1947 Reinhardt2872.2 X 2,974,393 3/1961 Hollowell 2872.2 X 3,122,140 2/1964 Crowe156-148 XR 3,199,166 8/1965 Petersik 284 LOUIS K. RIMRODT, PrimaryExaminer.

US. Cl. X.R.

